Battery pole piece, manufacturing method thereof and battery

Abstract

The invention provides a battery pole piece, a manufacturing method thereof and a battery. The method comprises the following steps: providing active substance slurry; coating the first surface of the current collector with active substance slurry, and forming a first active substance layer on the first surface of the current collector; the first active material layer and the current collector are punched, a plurality of first layer holes are formed in the first active material layer, a plurality of second layer holes are formed in the current collector, and each first layer hole is aligned and communicated with one second layer hole; the second surface of the current collector is coated with active substance slurry, the active substance slurry enters the first layer holes through the second layer holes so as to form a second active substance layer on the second surface of the current collector, and the second active substance layer penetrates through the second layer holes to be connected with the first active substance layer. The second active material layer penetrates through the second layer hole of the current collector and is connected with the first active material layer, so that the adhesiveness of the active material is stronger, the characteristic of high energy density of a thick electrode is effectively exerted, and the performance of the pole piece and the battery is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery manufacturing, and particularly relates to a battery electrode sheet, a manufacturing method thereof, and a battery. Background Art

[0002] A lithium-ion battery mainly consists of a positive electrode, a negative electrode, an electrolyte, and a separator. Among them, Li+ reversibly intercalates and deintercalates between the positive electrode and the negative electrode through the separator, and the electrolyte is the carrier for Li+ to transport therein. To ensure the performance of the battery, it is required that the electrolyte must completely infiltrate the positive electrode, the negative electrode, and the separator to form a Li+ conduction path. If the infiltration is insufficient, the ion transport path becomes longer, hindering the shuttling of lithium ions between the positive and negative electrodes. The electrode sheet that does not contact the electrolyte cannot participate in the battery electrochemical reaction. At the same time, the battery interface resistance increases, affecting the performance of the lithium-ion battery such as capacity, rate performance, and service life.

[0003] Currently, the two mainstream methods for manufacturing battery cells are winding and stacking. The infiltration of the wound battery cell is relatively poor. One reason is due to structural limitations, and the electrolyte can only penetrate from bottom to top. The other reason is that in order to make the structure compact, the hot pressing method is usually used to press the battery cell tightly. Both of them have an impact on the infiltration of the electrode sheet and will restrict the performance of the battery.

[0004] With the increasing requirements for battery performance, thick electrodes have become the current mainstream trend. However, the increase in electrode thickness restricts the infiltration ability of the electrolyte in the electrode sheet and also affects the peel strength of the electrode sheet. Summary of the Invention

[0005] Based on this, it is necessary to provide a battery electrode sheet, a manufacturing method thereof, and a battery for the above technical problems.

[0006] A manufacturing method of a battery electrode sheet includes:

[0007] Providing an active material slurry;

[0008] Coating the active material slurry on a first surface of a current collector to form a first active material layer on the first surface of the current collector;

[0009] Punching holes in the first active material layer and the current collector to form a plurality of first-layer holes in the first active material layer and a plurality of second-layer holes in the current collector, and each of the first-layer holes is aligned and communicated with one of the second-layer holes;

[0010] Coating the active material slurry on a second surface of the current collector, and the active material slurry enters the first-layer holes through the second-layer holes to form a second active material layer on the second surface of the current collector, and the second active material layer passes through the second-layer holes and is connected to the first active material layer.

[0011] In one embodiment, each of the first-layer holes is set to at least one of the following cases:

[0012] The aperture of each of the first-layer holes is 10 to 80 μm;

[0013] The spacing between adjacent first-layer holes is 1 to 10 mm.

[0014] In one embodiment, after the step of coating the active material slurry on the second surface of the current collector and the active material slurry enters the first-layer holes through the second-layer holes, the method further includes:

[0015] Etching the second active material layer to form a plurality of concave structures on the surface of the second active material layer, wherein each of the concave structures does not penetrate the second active material layer.

[0016] In one embodiment, the concave structure is set to at least one of the following:

[0017] The concave structure is a third-layer hole, and each of the third-layer holes is a blind hole;

[0018] The concave structure is a strip-shaped groove;

[0019] The concave structure is a zigzag groove or an annular groove.

[0020] In one embodiment, each of the third-layer holes is set to at least one of the following cases:

[0021] The aperture of each of the third-layer holes is 10 to 80 μm;

[0022] The spacing between adjacent third-layer holes is 1 to 10 mm.

[0023] In one embodiment, the step of etching the second active material layer to form a plurality of third-layer holes on the surface of the second active material layer includes:

[0024] Using a laser to etch the second active material layer, and the etching depth is less than the thickness of the second active material layer, so as to form a plurality of the concave structures on the surface of the second active material layer.

[0025] In one embodiment, the step of punching holes in the first active material layer and the current collector to form a plurality of first-layer holes in the first active material layer and a plurality of second-layer holes in the current collector includes:

[0026] Laser is emitted from the side of the first active material layer facing away from the current collector towards the first active material layer and the current collector to punch holes in the first active material layer and the current collector, forming a plurality of first-layer holes in the first active material layer and a plurality of second-layer holes in the current collector.

[0027] In one embodiment, in the step of coating the active material slurry on the first side of the current collector, the density of the coated active material slurry is 120 g / m2;

[0028] and / or

[0029] In the step of coating the active material slurry on the second side of the current collector, the density of the coated active material slurry is 120 g / m2.

[0030] A battery electrode plate includes: a first active material layer, a current collector, and a second active material layer;

[0031] The first active material layer is disposed on the first side of the current collector, the second active material layer is disposed on the second side of the current collector, and the first side and the second side of the current collector are arranged opposite to each other;

[0032] The first active material layer is provided with a plurality of first-layer holes, the current collector is provided with a plurality of second-layer holes, each first-layer hole is aligned and communicated with a second-layer hole, the second active material layer includes a second-layer body and a plurality of connecting portions, the second-layer body is disposed on the second side of the current collector, each connecting portion protrudes from the surface of the second-layer body facing the current collector, and each connecting portion is inserted into each second-layer hole one by one, and at least a part of each connecting portion protrudes to the first side of the current collector to be connected with the first active material layer.

[0033] A battery includes the battery electrode plate described in the above embodiment.

[0034] The above battery electrode plate, its manufacturing method, and battery form first-layer holes in the first active material layer, enabling the second active material layer to penetrate the second-layer holes of the current collector and connect with the first active material layer, making the electrode plate have good wettability and stronger adhesion of the active material, and being able to more effectively exert the characteristics of a thick electrode with high energy density, thereby improving the performance of the electrode plate and the battery. And since the use of perforated foil is avoided, the risk of coating breakage caused by foil defects can be reduced, which is beneficial to improving the yield and effectively reducing the cost. Description of the Drawings

[0035] Figure 1 It is a schematic flow chart of the manufacturing method of a button battery in one embodiment;

[0036] Figure 2Schematic diagram of the process of laser drilling on the first active material layer and the current collector in a button battery in one embodiment;

[0037] Figure 3 Schematic plan view of the first active material layer and the current collector after drilling in one embodiment;

[0038] Figure 4 Schematic diagram of the process of laser etching on the second active material layer to drill holes in one embodiment;

[0039] Figure 5 Schematic cross-sectional view of a battery electrode in one embodiment.

[0040] Explanation of reference numerals:

[0041] 10. Battery electrode; 100. Current collector; 110. First active material layer; 120. Second active material layer; 101. First side of the current collector; 102. Second side of the current collector; 201. First layer of holes; 202. Second layer of holes; 203. Third layer of holes; 510. Laser. Detailed implementation manners

[0042] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0043] Embodiment 1

[0044] In this embodiment, as Figure 1 shown, a manufacturing method of a battery electrode is provided, which includes:

[0045] Step 110: Provide an active material slurry.

[0046] In this embodiment, the active material slurry includes an active material, a conductive agent, a binder and a dispersant. Among them, the ratio of the active material, the conductive agent, the binder and the dispersant is: 96.0:2:1.5:0.5. In this embodiment, the active material slurry is obtained by mixing the active material, the conductive agent, the binder and the dispersant in a ratio of 96.0:2:1.5:0.5.

[0047] In some other embodiments, the active material, the conductive agent, the binder and the dispersant in the active material slurry can also be mixed in other ratios.

[0048] Step 120: Coat the active material slurry on the first side of the current collector to form a first active material layer on the first side of the current collector.

[0049] In this embodiment, the current collector is also called a foil. As Figure 2 shown, the active material slurry is coated on the first surface 101 of the current collector 100, and then dried to form the first active material layer 110.

[0050] Step 130: Punch holes in the first active material layer and the current collector to form a plurality of first-layer holes in the first active material layer and a plurality of second-layer holes in the current collector, and each of the first-layer holes is aligned and communicated with one of the second-layer holes.

[0051] In this embodiment, as Figure 2 and Figure 3 shown, using the punching technology, punch holes in the first active material layer 110 and the current collector 100. In some embodiments, holes can be punched from one side of the first active material layer and penetrate through to the current collector, so as to form mutually communicated first-layer holes and second-layer holes on the first active material layer and the current collector respectively; in some embodiments, holes can also be punched from one side of the current collector and penetrate through to the first active material layer, and mutually communicated first-layer holes 201 and second-layer holes 202 are formed on the first active material layer and the current collector respectively.

[0052] Step 140: Coat the active material slurry on the second surface of the current collector, and the active material slurry penetrates into the first-layer holes through the second-layer holes to form a second active material layer on the second surface of the current collector, and the second active material layer passes through the second-layer holes and is connected to the first active material layer.

[0053] In this embodiment, the active material slurry is coated on the second surface of the current collector, and the coated active material slurry penetrates through the second-layer holes of the current collector to the first surface of the current collector and is connected to the first active material layer. The active material slurry on the second surface is dried to obtain a second active material layer including a second-layer body and a plurality of connecting parts. The second-layer body is disposed on the second surface of the current collector, each connecting part protrudes from the surface of the second-layer body facing the current collector, and each connecting part is inserted into one of the second-layer holes one by one, and at least part of each connecting part protrudes to the first surface of the current collector and is connected to the first active material layer.

[0054] In this embodiment, since the active material slurry penetrates to the first surface of the current collector and is connected to the first active material layer when being coated on the second surface of the current collector, the second active material layer can be connected to the first active material layer, which plays a role in strengthening the adhesion, and effectively improves the adhesion of the active material layers on the two opposite surfaces of the current collector.

[0055] Step 150: Etch the second active material layer to form a plurality of concave structures on the surface of the second active material layer, wherein each of the concave structures does not penetrate the second active material layer.

[0056] In this embodiment, as Figure 4 shown, the second active material layer 120 is etched to form a recessed structure on the surface of the second active material layer that does not penetrate the second active material layer, that is, the etching thickness is less than the thickness of the second active material layer, thereby avoiding the recessed structure from penetrating to the current collector.

[0057] It is worth mentioning that in the prior art, in order to improve the peel strength and wettability of the electrode, perforated foils are used, that is, the foils are provided with perforations. However, such foils have problems in the production process. On the one hand, its processing process is more difficult and the cost is higher compared to ordinary non-perforated foils. On the other hand, since multiple perforations are provided on the foils, the foil structure is unstable, defects are likely to occur, and the tape is more likely to break during traction.

[0058] In this application, an ordinary non-perforated foil is used as the current collector for coating the active material slurry. After the first active material layer is coated and formed on the first side of the current collector, punching is performed, thereby replacing the perforated foil used in the prior art, reducing the risk of coating tape breakage caused by foil defects, being beneficial to improving the yield, and effectively reducing the cost.

[0059] In addition, in this embodiment, the first layer of holes is formed on the first active material layer, and the recessed structure is formed on the second active material layer. In this way, it is beneficial to the infiltration of the electrolyte, thereby shortening the standing time after injection, and at the same time achieving the purpose of improving the battery performance.

[0060] It is worth mentioning that the battery electrode sheet in this embodiment uses a thick electrode sheet. For the prior art, due to the relatively high amount of auxiliary materials in the thick electrode, the peel strength is low and the infiltration is difficult, and the problem is more significant. In this application, by forming the first layer of holes on the first active material layer and the second layer of holes on the second active material layer, and making the second layer of holes in the second active material layer penetrate the current collector to connect with the first active material layer, the electrode sheet has good wettability and stronger adhesion of the active material, can more effectively exert the characteristics of the high energy density of the thick electrode, and thus improve the performance of the electrode sheet and the battery.

[0061] In one embodiment, the aperture diameter of each of the first-layer holes is 10 to 80 μm. In this embodiment, the aperture diameter of the first-layer holes is equal to that of the second-layer holes, and the aperture diameter of each of the second-layer holes is 10 to 80 μm. In this embodiment, setting the aperture diameter of the first-layer holes to 10 to 80 μm can, on the one hand, effectively improve the structural stability of the first active material layer and the current collector, and on the other hand, effectively improve the adhesion of the active material. It is worth mentioning that if the aperture diameters of the first-layer holes and the second-layer holes are too small, the connection between the first active material layer and the second active material layer will not be tight enough, the adhesion of the active material cannot be effectively improved, and the peeling force cannot be increased. If the aperture diameters of the first-layer holes and the second-layer holes are too large, the structure of the first active material layer and the current collector will be unstable. Therefore, in this embodiment, setting the aperture diameters of the first-layer holes and the second-layer holes to 10 to 80 μm can not only effectively improve the adhesion of the active material and increase the peeling force of the electrode sheet, but also effectively improve the structural stability of the first active material layer and the current collector.

[0062] In one embodiment, the spacing between adjacent ones of the first-layer holes is 1 to 10 mm. In this embodiment, the spacing between the second-layer holes is equal to the spacing between the first-layer holes. For example, the spacing between the second-layer holes is 1 to 10 mm. It should be understood that if the spacing between the first-layer holes and the spacing between the second-layer holes are too large, it is not conducive to the connection between the second active material layer and the first active material layer, making the connection between the two unstable and unable to effectively improve the adhesion. If the spacing between the first-layer holes and the spacing between the second-layer holes are too small, the holes will be too dense, resulting in an unstable structure of the current collector and the first active material layer. Therefore, in this embodiment, setting the spacing between the first-layer holes and the spacing between the second-layer holes to 1 to 10 mm can effectively avoid the inability to form an effective connection force due to too large a spacing, avoid the inability to form an effective adhesion, and also avoid the instability of the structure of the current collector and the first active material layer due to too high a hole density.

[0063] In one embodiment, the recessed structure is set as at least one of the following: the recessed structure is the third-layer holes, and each of the third-layer holes is a blind hole; the recessed structure is a strip-shaped groove; the recessed structure is a square-shaped groove or an annular groove.

[0064] In this embodiment, the function of the recessed structure is to reduce the local thickness of the second active material layer, thereby facilitating the infiltration of the electrolyte. The recessed structure can be a blind hole, a linear groove, or a square-shaped or annular groove.

[0065] In one embodiment, as Figure 4 shown, the recessed structure is the third-layer holes 203, and each of the third-layer holes is a blind hole. In this embodiment, the recessed structure is set as the third-layer blind holes.

[0066] In one embodiment, the pore diameter of each of the third-layer holes is 10 to 80 μm. In this embodiment, setting the pore diameter of the second-layer holes to 10 to 80 μm can effectively improve the structural stability of the second active material layer and make the infiltration effect of the electrolyte better. It should be understood that if the pore diameter of the third-layer holes is too small, the wettability of the electrode sheet cannot be effectively improved, and if the pore diameter of the third-layer holes is too large, the structure of the second active material layer will be unstable. Therefore, in this embodiment, setting the pore diameter of the third-layer holes to 10 to 80 μm can not only effectively improve the wettability of the electrode sheet, but also effectively improve the structural stability of the second active material layer.

[0067] In one embodiment, the depth of each of the third-layer holes is 30 to 90 μm. It should be understood that if the depth of the third-layer holes is too small, the wettability of the electrode sheet cannot be effectively improved, and if the depth of the third-layer holes is too large, the structure of the second active material layer will be unstable. Therefore, in this embodiment, setting the depth of the third-layer holes to 30 to 90 μm can not only effectively improve the wettability of the electrode sheet, but also effectively improve the structural stability of the second active material layer.

[0068] In one embodiment, the distance between adjacent third-layer holes is 1 to 10 mm. In this embodiment, setting the distance between the third-layer holes to 1 to 10 mm can make the infiltration effect of the electrolyte better, and can also prevent the structure of the second active material layer from being unstable due to excessive pore density.

[0069] In one embodiment, each of the third-layer holes is aligned with each of the second-layer holes. In this embodiment, each third-layer hole is aligned with a second-layer hole and a first-layer hole. Since the third-layer holes are blind holes, there is no communication between the third-layer holes and the second-layer holes and the first-layer holes, which reduces the local thickness of the electrode sheet and makes the infiltration effect of the electrolyte better.

[0070] In one embodiment, the step of punching holes in the first active material layer and the current collector, forming a plurality of first-layer holes in the first active material layer, and forming a plurality of second-layer holes in the current collector includes:

[0071] Emitting laser light from the side of the first active material layer facing away from the current collector to the first active material layer and the current collector to punch holes in the first active material layer and the current collector, forming a plurality of first-layer holes in the first active material layer, and forming a plurality of second-layer holes in the current collector.

[0072] In this embodiment, if Figure 2As shown, using the laser head 510, the laser drilling technology is adopted to drill holes in the first active material layer 110 and the current collector 100. Specifically, during the process, holes are drilled in the first active material layer 110 on the side facing away from the current collector 100 and penetrate through to the current collector 100, punching through the first active material layer 110 and the current collector 100, so as to form a penetrating through-hole in the first active material layer and the current collector, forming a plurality of first-layer holes 201 in the first active material layer 110 and a plurality of second-layer holes 202 in the current collector 100.

[0073] In one embodiment, the step of etching the second active material layer to form a plurality of third-layer holes on the surface of the second active material layer includes: etching the second active material layer with a laser, and the etching depth is less than the thickness of the second active material layer, and a plurality of the concave structures are formed on the surface of the second active material layer.

[0074] In this embodiment, as Figure 4 shown, using the laser head 510, the laser etching technology is adopted to etch and drill holes in the second active material layer 120. The etching depth is less than the thickness of the second active material layer, so that the formed concave structure cannot penetrate through the second active material layer. In this way, the wettability of the electrolyte to the electrode sheet can be effectively improved.

[0075] In one embodiment, in the step of coating the active material slurry on the first surface of the current collector, the density of the coated active material slurry is 120 g / m 2 ;

[0076] In one embodiment, in the step of coating the active material slurry on the second surface of the current collector, the density of the coated active material slurry is 120 g / m 2 .

[0077] In this embodiment, the density of the active material slurry coated on the surface of the current collector is 120 g / m 2 , so that it is beneficial to improve the wetting effect of the electrolyte.

[0078] In other embodiments, the coated active material slurry can adopt other densities, which will not be described in detail herein.

[0079] Embodiment Two

[0080] In this embodiment, as Figure 5 shown, a battery electrode sheet 10 is provided, including: a first active material layer 110, a current collector 100, and a second active material layer 120;

[0081] The first active material layer 110 is disposed on the first surface of the current collector 100, and the second active material layer 120 is disposed on the second surface of the current collector 100. The first surface and the second surface of the current collector 100 are arranged opposite to each other;

[0082] The first active material layer 110 is provided with a plurality of first layer holes 201, and the current collector 100 is provided with a plurality of second layer holes 202. Each of the first layer holes 201 is aligned and communicated with one of the second layer holes 202. The second active material layer 120 includes a second layer body and a plurality of connecting portions. The second layer body is disposed on the second surface of the current collector 100. Each of the connecting portions protrudes from the surface of the second layer body facing the current collector 100, and each of the connecting portions is inserted into each of the second layer holes 202 one by one, and at least a part of each of the connecting portions protrudes to the first surface of the current collector 100 to be connected to the first active material layer 110.

[0083] In this embodiment, the second active material layer 120 passes through the second layer holes 202 to be connected to the first active material layer 110, so that the adhesion of the active material is stronger, effectively improving the peeling force of the battery electrode sheet 10 and making the performance of the battery electrode sheet 10 better.

[0084] In addition, the connecting portion protrudes from the second layer hole 202 to the first surface of the current collector 100 and is inserted into the first layer hole 201 to close the first layer hole 201. In some embodiments, the length of the connecting portion inserted into the first layer hole 201 is less than the depth of the first layer hole 201, so that the first layer hole 201 forms a blind hole structure. In this way, the electrode sheet has good wettability.

[0085] In one embodiment, a plurality of concave structures are formed on the surface of the second active material layer 120, and each of the concave structures does not penetrate the second active material layer 120.

[0086] It is worth mentioning that the battery electrode sheet 10 in this embodiment adopts a thick electrode sheet. For the prior art, due to the high amount of auxiliary materials in the thick electrode, the peeling force is low and the infiltration is difficult, and the problem is more significant. In the present application, by forming the first layer holes 201 on the first active material layer 110, forming the concave structures on the second active material layer 120, and making the second active material layer 120 penetrate through the second layer holes 202 of the current collector 100 to be connected to the first active material layer 110, the electrode sheet has good wettability, the adhesion of the active material is stronger, and the high energy density characteristic of the thick electrode can be more effectively exerted, thereby improving the performance of the electrode sheet and the battery.

[0087] In one embodiment, the recessed structure is set as at least one of the following: the recessed structure is the third-layer holes 203, and each of the third-layer holes 203 is a blind hole; the recessed structure is a strip-shaped groove; the recessed structure is a square-shaped groove or an annular groove.

[0088] In this embodiment, the function of the recessed structure is to reduce the local thickness of the second active material layer 120, thereby facilitating the infiltration of the electrolyte. The recessed structure can be a blind hole, a linear groove, or a square-shaped or annular groove.

[0089] In one embodiment, the recessed structure is the third-layer holes 203, and each of the third-layer holes 203 is a blind hole. In this embodiment, the recessed structure is set as the blind third-layer holes 203.

[0090] In this embodiment, the first-layer holes 201 are formed on the first active material layer 110, and the third-layer holes 203 are formed on the second active material layer 120. In this way, it is beneficial to the infiltration of the electrolyte, thereby shortening the standing time after injection and simultaneously achieving the purpose of improving the battery performance.

[0091] In one embodiment, the aperture of each of the first-layer holes 201 is 10 - 80 μm. In this embodiment, the aperture of the first-layer holes 201 is equal to that of the second-layer holes 202, and the aperture of each of the second-layer holes 202 is 10 - 80 μm. In this embodiment, the aperture of the first-layer holes 201 is set to 10 - 80 μm. On the one hand, it can effectively improve the structural stability of the first active material layer 110 and the current collector 100. On the other hand, it can effectively improve the adhesion of the active material. It is worth mentioning that if the apertures of the first-layer holes 201 and the second-layer holes 202 are too small, the connection between the first active material layer 110 and the second active material layer 120 will not be tight enough, and the adhesion of the active material cannot be effectively improved, and the peel strength cannot be improved. If the apertures of the first-layer holes 201 and the second-layer holes 202 are too large, the structure of the first active material layer 110 and the current collector 100 will be unstable. Therefore, in this embodiment, the apertures of the first-layer holes 201 and the second-layer holes 202 are set to 10 - 80 μm, which can not only effectively improve the adhesion of the active material and the peel strength of the electrode sheet, but also effectively improve the structural stability of the first active material layer 110 and the current collector 100.

[0092] In one embodiment, the spacing between adjacent first-layer holes 201 is 1 to 10 mm. In this embodiment, the spacing between second-layer holes 202 is equal to the spacing between first-layer holes 201. For example, the spacing between second-layer holes 202 is 1 to 10 mm. It should be understood that if the spacing between first-layer holes 201 and the spacing between second-layer holes 202 are too large, it is not conducive to the connection between the second active material layer 120 and the first active material layer 110, making the connection between the two unstable and unable to effectively improve the adhesion. If the spacing between first-layer holes 201 and the spacing between second-layer holes 202 are too small, the holes are too dense, resulting in an unstable structure of the current collector 100 and the first active material layer 110. Therefore, in this embodiment, setting the spacing between first-layer holes 201 and the spacing between second-layer holes 202 to 1 to 10 mm can effectively avoid the inability to form an effective connection force due to too large a spacing, avoid the inability to form an effective adhesion, and also avoid the instability of the structure of the current collector 100 and the first active material layer 110 due to too high a hole density.

[0093] In one embodiment, the aperture of each third-layer hole 203 is 10 to 80 μm. In this embodiment, setting the aperture of the second-layer holes 202 to 10 to 80 μm can effectively improve the stability of the structure of the second active material layer 120 and make the infiltration effect of the electrolyte better. It should be understood that if the aperture of the third-layer holes 203 is too small, the wettability of the electrode sheet cannot be effectively improved, and if the aperture of the third-layer holes 203 is too large, the structure of the second active material layer 120 is unstable. Therefore, in this embodiment, setting the aperture of the third-layer holes 203 to 10 to 80 μm can not only effectively improve the wettability of the electrode sheet, but also effectively improve the stability of the structure of the second active material layer 120.

[0094] In one embodiment, the depth of each third-layer hole 203 is 30 to 90 μm. It should be understood that if the depth of the third-layer holes 203 is too small, the wettability of the electrode sheet cannot be effectively improved, and if the depth of the third-layer holes 203 is too large, the structure of the second active material layer 120 is unstable. Therefore, in this embodiment, setting the depth of the third-layer holes 203 to 30 to 90 μm can not only effectively improve the wettability of the electrode sheet, but also effectively improve the stability of the structure of the second active material layer 120.

[0095] In one embodiment, the depth of each of the third-layer holes 203 is 30 to 90 μm. It should be understood that if the depth of the third-layer holes 203 is too small, the wettability of the electrode sheet cannot be effectively improved, while if the depth of the third-layer holes 203 is too large, the structure of the second active material layer 120 will be unstable. Therefore, in this embodiment, the aperture of the third-layer holes 203 is set to 30 to 90 μm, which can not only effectively improve the wettability of the electrode sheet, but also effectively improve the stability of the structure of the second active material layer 120.

[0096] In one embodiment, the distance between adjacent third-layer holes 203 is 1 to 10 mm. In this embodiment, setting the distance between the third-layer holes 203 to 1 to 10 mm can make the infiltration effect of the electrolyte better, and can also avoid the instability of the structure of the second active material layer 120 due to excessive hole density.

[0097] In one embodiment, each of the third-layer holes 203 is aligned with each of the second-layer holes 202. In this embodiment, each third-layer hole 203 is aligned with a second-layer hole 202 and a first-layer hole 201. Since the third-layer holes 203 are blind holes, the third-layer holes 203 are not connected to the second-layer holes 202 and the first-layer holes 201, which reduces the local thickness of the electrode sheet and makes the infiltration effect of the electrolyte better.

[0098] Embodiment Three

[0099] In this embodiment, a battery is provided, including the battery electrode sheet described in any of the above embodiments.

[0100] Embodiment Four

[0101] In this embodiment, the process of manufacturing the battery electrode sheet and the battery is as follows:

[0102] 1. Slurry preparation: Prepare the slurry in a certain proportion, such as: active material: conductive agent: binder: dispersant = 96.0: 2: 1.5: 0.5, but not limited to this formula.

[0103] 2. Coating on side A: Coat the above slurry and ordinary foil at a certain surface density, such as: 120 g / m2, but not limited to this surface density. After coating on side A, dry it.

[0104] 3. Laser drilling: Use a laser to drill holes in the single-sided electrode sheet. The aperture is 10 to 80 μm, and the distance between each small hole is 1 to 10 mm. Drill directly through the electrode sheet to form continuous and dense small holes. It should be noted that to ensure the tensile strength, the distance between the small holes needs to be adjusted according to the actual processing.

[0105] 4. Coating on the B side: The single-sided electrode plate with holes is coated on the B side. The coating material on the B side can penetrate through the small holes to the A side, playing a role in strengthening the adhesion. It can be dried by the conventional coating method.

[0106] 5. Laser etching: After coating on the B side, laser etching is carried out, but the foil material is not penetrated. The etching depth is lower than the thickness of the dressing material, the pore diameter is 10 - 80 μm, and the distance between each small hole is 1 - 10 mm. The etching is not limited to the hole structure and can also be linear, square-shaped, etc.

[0107] 6. After the electrode plate is etched, it is normally rolled and transferred, and the battery is made by winding or stacking. The subsequent processes are no different from the current mainstream manufacturing process.

[0108] In the above embodiments, the method for manufacturing the battery electrode plate can be summarized as: coating the active material slurry on the A side of the current collector → laser drilling → coating the active material slurry on the B side of the current collector → laser etching. This method does not require the use of a perforated current collector, can achieve its effect, and improves the processing reliability and wettability of the electrode plate; the obvious feature is that the position of the holes on the A side is highly consistent with the position of the perforations of the current collector.

[0109] In this embodiment, the battery made by this method has better liquid retention performance. The negative electrode plate is made by this method, with better adhesion and better suppression of swelling.

[0110] In addition, extending this electrode manufacturing method to the coating application of thick electrodes can better exert the advantages brought by this manufacturing method.

[0111] Performance parameter comparison:

[0112] In this part, the electrode plate peeling force and electrolyte diffusion time of the battery electrode plates manufactured in the experimental group and the control group are respectively compared. Among them, the experimental group is manufactured by using the manufacturing method of the battery electrode plate in the above embodiments, and the control group is the battery electrode plate manufactured by the traditional method. The comparison results are shown in Tables 1 to 2.

[0113] Table 1 Comparison of electrode plate peeling force between the experimental group and the control group

[0114]

[0115] Table 2 Comparison of electrolyte diffusion time between the experimental group and the control group

[0116]

[0117] From the above experimental group and control group, it can be seen that the peeling force of the electrode plate manufactured by using the above battery electrode plate manufacturing method of the present application is significantly improved compared with the control group, and the adhesion of the active material is stronger.

[0118] In addition, blind holes are formed on the second active material layer of the experimental group to form a second layer of holes, so that the electrode sheet has good wettability and the diffusion time of the electrolyte is significantly reduced compared with the control group.

[0119] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0120] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A method for manufacturing a battery electrode sheet, characterized in that, Comprising: Providing an active material slurry; Coating the active material slurry on the first surface of the current collector to form a first active material layer on the first surface of the current collector; Punching holes in the first active material layer and the current collector to form a plurality of first-layer holes in the first active material layer and a plurality of second-layer holes in the current collector, with each of the first-layer holes aligned and communicating with one of the second-layer holes; Coating the active material slurry on the second surface of the current collector, and the active material slurry enters the first-layer holes through the second-layer holes to form a second active material layer on the second surface of the current collector, and the second active material layer passes through the second-layer holes and is connected to the first active material layer.

2. The method according to claim 1, wherein Each of the first-layer holes is set to at least one of the following conditions: The aperture of each of the first-layer holes is 10 - 80 μm; The spacing between adjacent first-layer holes is 1 - 10 mm.

3. The method according to claim 1, characterized in that After the step of coating the active material slurry on the second surface of the current collector and the active material slurry entering the first-layer holes through the second-layer holes, it further includes: Etching the second active material layer to form a plurality of concave structures on the surface of the second active material layer, wherein each of the concave structures does not penetrate the second active material layer.

4. The method according to claim 3, characterized in that, The concave structures are set to at least one of the following: The concave structures are third-layer holes, and each of the third-layer holes is a blind hole; The concave structures are strip-shaped grooves; The concave structures are square-shaped grooves or circular grooves.

5. The method according to claim 4, characterized in that Each of the third-layer holes is set to at least one of the following conditions: The aperture of each of the third-layer holes is 10 - 80 μm; The spacing between adjacent third-layer holes is 1 - 10 mm.

6. The method according to any one of claims 3 to 5, characterized in that The step of etching the second active material layer to form a plurality of third-layer holes on the surface of the second active material layer includes: Etching the second active material layer with a laser, and the etching depth is less than the thickness of the second active material layer to form a plurality of the concave structures on the surface of the second active material layer.

7. The method according to any one of claims 1-5, characterized in that, The step of punching holes in the first active material layer and the current collector to form a plurality of first-layer holes in the first active material layer and a plurality of second-layer holes in the current collector includes: Emitting a laser from the side of the first active material layer facing away from the current collector to the first active material layer and the current collector to punch holes in the first active material layer and the current collector, and forming a plurality of first-layer holes in the first active material layer and a plurality of second-layer holes in the current collector.

8. The method according to any one of claims 1 to 5, characterized in that In the step of coating the active material slurry on the first side of the current collector, the density of the coated active material slurry is 120 g / m 2 ; And / or In the step of coating the active material slurry on the second side of the current collector, the density of the coated active material slurry is 120 g / m 2 .

9. A battery electrode plate, characterized in that, Comprising: A first active material layer, a current collector, and a second active material layer; The first active material layer is disposed on the first surface of the current collector, the second active material layer is disposed on the second surface of the current collector, and the first surface and the second surface of the current collector are arranged opposite to each other; The first active material layer is provided with a plurality of first layer holes, the current collector is provided with a plurality of second layer holes, each of the first layer holes is aligned and communicated with one of the second layer holes, the second active material layer includes a second layer body and a plurality of connecting portions, the second layer body is disposed on the second surface of the current collector, each of the connecting portions protrudes from a surface of the second layer body facing the current collector, and each of the connecting portions is inserted into one of the second layer holes correspondingly, and at least a part of each of the connecting portions protrudes to the first surface of the current collector to be connected with the first active material layer.

10. A battery, characterized in that, Comprising the battery electrode plate according to claim 9.

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